Movable-chaser tap



Nov. 22, 1932. A. F. BREITENSTEIN MOVABLE CHASER TAP Filed Jan. 2, 1931 2 Sheets-Sheet Nov. 22, 1932- A. F. BREITENSTEIN MOVABLE CHASER TAP 2 Sheets-Sheet 2 Filed Jan. 2, 1931 Patented Nov. 22, 1932 ETE 5|! ALBERT F. BREITENSTEIN, OF NEW HAVEN, CONNECTICUT, ASSIGNOB TO THE GEOMETRIC TOOL COMPANY, OF NEW HAVEN, CONNECTICUT, A CORPORATION MOVABLE-CHASER TAP Application" filed January 2, 1931. Serial No. 506,156.

This invention relates to an improvement in taps of the type having movable chasers that is to say, taps in which the Chasers are movable for purposes of adjustment or movable, as in collapsing taps, for shifting the chaser-s from their cutting position to a retired position, and vice versa.

The main object of this invention is to provide a tap of the movable-chaser type which will possess superior resistance to breakage and distortion and superior vaccuracy over a long period of use.

A further object of this invention is to provide a rugged and reliable tap of the type referred to characterized by diametrical compactness.

With the above and other objects in view as will appear from the following, my invention consists in a movable-chaser tap having certain details of construction and combinations .of parts as will be hereinafter described and particularly recited in the claims.

7 In the accompanying drawings:

Fig. 1 is a view in side elevation of one form which a movable-chaser tap embodying my invention may assume; I

Fig. 2 is a view thereof in front elevation;

Fig. 3 is a view partly in side-elevation and partly in central longitudinal section, with the parts in the positions due to them when the chasers are at substantially 'thelimit of their outward movement;

Fig. 4 is a transverse sectional View taken on the line 4-4l of Fig. 3;

Fig. 5 is a View corresponding to Fig. 3 but showing the parts in the positions due to them when the chasers are at substantially the limit of their inward movement;

Fig. 6 is a transverse sectional View taken on the line 6-6 of Fig. 5;

Fig. 7 is a perspective View of one of the movable chasers detached;

Fig. 8 is a perspective view of the chaseroperating plunger detached; vand i Fig. 9 is a corresponding view of the bodymember of the tap-structure.

In the particular embodiment of my invention herein chosen for illustration, I employ a body-member 10 provided at its forward end witha cylindrical head-portion 1,1 and a shank 12 of relatively-small diameter pro- 1 jecting rearwardly from the said head-portion. The-said body-member is provided with an ax'ial'bore 13 extending therethrough from end to end, the forward end of which is enlarged to form a chamber 14, which latter is intersected by three (more or less) radial guide-ways or grooves '15 opening through the forward face of the head-portion 11 and intersecting the said chamber 14 and the periphery of the said head-portion.

Reciprocating in the axial chamber 14: is the enlarged forward end 16 of a chaseractuating plunger 17 which is formed about midway the length of its enlarged forward end 16 with three guide-lugs '18, each of which is of proper width to slide smoothly back and forth in and out of i the radial grooves 15 in the head 11 ofthebody-member 10. While there is necessarily some degree of c'learanceor tolerance between the lugs 18 and their respective grooves 15, so that some degree of relative lateral movement will take place, nevertheless this interhtting of'the lugs 18 and grooves 15 will serve, in the construction shown, to prevent appreciable rotaryd-is placement of the plunger 17 with respect to the body-member 10. Each 'guide lug '18 is centrally split or bifurcated, as s'hown,to provide a guide-passage 19 for thereception of'a chaser 20 of which latter three areemployed, i. e., one for each guide-lug.

In line with each of the guide-passages 19 respectively, the forward end ofthe' portion '16 ofthe plunger 17 is formed with a groove '20", the inner or bottom face of which constitutes a sloping cam-surface 21,-upon'which rides the similarly-slopedunder-face 22 of one of the chasers 20 before referred to.

Each chaser 20 above referred "to is of substantially .L-shaped form and consists of a body-portion 23 and a forwardly-extending tang 24: formed upon its outer surface with serrations '25 for cutting screw-threads.

The rear face 26 of each chaser 2O bears against the back-wall 27 of the particular groove 15 in which it is mounted and 'is retained in place by the inturned-flange 28 of a cup-shaped retaining-member 29 secured in place over'thehead-portion 11 of the bodymember by means of screws 30. The flange 28 above referred to is formed with three radial slots 31 for the clearance of the forward portions of the respective chasers and bears against a stepped-back surface 32 formed upon the body-portion 26 of each chaser near the front upper edge thereof.

Preferably and as herein shown, each chaser is urged radially. inward to maintain'its sloping surface 22 in engagement with its complementary cam-surface 21 upon the plunger 17 by means of an arcuate spring 33 having its free end 34 hearing against the outer surface of its complementary chaser and secured, by means of a screw 35, in an arcuate groove 36, one of which latter is formed in the periphery of the head-portion 11 of the body-member between the respective radial grooves 15 therein.

Any suitable means may be employed for moving the chaser-actuating plunger 17 back and forth with respect to the body-member 10, so that no detailed description of such a mechanism is required herein except to say that in the embodiment herein chosen for illustration, it is housed within a member 37 mounted upon the rearwardly-extending shank 12 of the body-member 10 and provided with a forwardly-extending flange 38 having a sliding engagement with the periphery of the cup-shaped retaining-member 29 to exclude dirt and chips from the mechanism.

From the foregoing description it will be seen that when the chaser-operating plunger 17 is moved forward, such, for instance, as from the position in which it is shown in Fig. 5, to the position in which it is shown in Fig. 3, the respective chasers 20 will be moved radially outward simultaneously by the engagement of the sloping under-face 22 of each chaser with the complementary camsurface 22 upon the said plunger. Conversely, when the chaser-operating plunger is moved rearward, such, for instance, as from the position shown in Fig. 3 to the position shown in Fig. 5, the chasers will be permitted to retire radially inward under the urge of their respective springs 33 or such other means as may be employed for that purpose.

The particular point to which I wish to call attention is the fact that the chasers in their radial movement are supported laterally by the offsetting guide-lugs 18 of the chaser-operating plunger and that the said guide-lugs move in the radial grooves 15 provided for them in the forward face of the body-member 10. By the construction ust referred to the chasers are adequately supported against lateral displacement with respect to the body-member through the intermediary of the said guide-lugs 18. It will further be noted that the chasers and particularly the outer ends thereof are supported by the side-walls of the respective grooves 20 created by forming the cam-surfaces 21.

A movable-chaser tap constructed in accordance with my invention not only provides for firmly supporting the chasers against torsional strains but also prevents the cramping of the parts which has been one of the outstanding objections to prior types of movable chaser-taps in which the rear ends of the chasers have been laterally supported directlyin the body-member of the tap-structure.

It will be understood by those skilled in the art that my invention may assume varied physical forms without departing from my inventive concept, and I, therefore, do not limit myself to the specific embodiment herein chosen for illustration, but only as indicated in the appended claims.

I claim:

1. In a movable-chaser tap, the combination with a body-member formed with a plurality of substantially-radial guide-ways; of a chaser-operating member mounted for reciprocating movement with respect to the said body-member and provided with subciprocating movement with respect to the said body-member and provided with substantially-radial bifurcated guide-lugs forming a unit with and reciprocating with the chaser-operating member itself and extending into the radial guide-ways in the said body-member for guidance thereby, and also formed with outwardly-facing cam-surfaces; and chasers respectively installed in the bifurcated guide-lugs of the said chaser-operating member for substantially radial movement with respect thereto and located in position to bear against the cam-surfaces thereof for being moved thereby.

3. In a movable-chaser tap, the combination with a body-member formed in its forward face with a plurality of substantiallyradial guide-grooves; of a chaser-operating member mounted for reciprocating movement with respect to the said body-member and provided with substantially-radial guide-lugs forming a unit with and reciprocating with the chaser-operating member itself and extending into the guide-grooves in the forward face of the said body-member; and chasers respectively installed in the guide-lugs of the said chaser-operating member for substantially radial movement with respect thereto and coacting with the said chaser-operating member for being so moved.

4. In a movable-chaser tap, the combination with a body-member formed in its forward face with a plurality of substantiallyradial guide-grooves; of a chaser-operating member mounted for reciprocating movement with respect to the said body-member and provided with substantially-radial bifurcated guide-lugs forming a unit with and reciprocating with the chaser-operating member itself and extending into the guide-grooves in the forward face of the said body-member for guidance thereby, and also formed with outwardly-facing cam-surfaces; and chasers respectively installed in the bifurcated guidelugs of the said chaser-operating member for substantially radial movement with respect thereto and located in position to bearagainst the cam-surfaces thereof for being moved thereof.

5. In a movable-chaser tap, the combination with a body-member formed with an axial bore and with a. plurality of substantially-radial guide-ways leading outward therefrom; of a chaser-operating member mounted in the axial bore in the said bodymember for reciprocating movement therein and provided with substantially-radial guidelugs forming a unit with and reciprocating with the chaser-operating member itself and extending into the radial guide-ways in the said body-member for guidance thereby; and chasers respectively installed in the guidelugs of the said chaser-operating member for substantially radial movement with respect thereto and coacting with the said chaser-operating member for being so moved.

6. In a movable-chaser tap, the combination with a body-member formed with an axial bore and with a plurality of substantially-radial guide-ways leading outward therefrom; of a chaser-operating member mounted in the axial bore in the said bodymember for reciprocating movement therein and provided with substantially-radial bifurcated guide-lugs forming a unit with and reciprocating with the chaser-operating member itself and extending into the radial guide-ways in the said body-member for guidance thereby; and chasers respectively mounted in the bifurcated guide-lugs of the said chaser-operating member for substantially radial movement with respect thereto and coacting with the said chaser-operating member for being so moved.

7. In a movable-chaser tap, the combination with a body-member; of a plurality of chasers; and a. combined chaser-operating and chaser-supporting member mounted for reciprocating movement with respect to the said body-member and provided with means reciprocating with it for laterally supporting the said chasers; the said means for laterally supporting the said chasers being in turn supported in the said body-member and acting as means to guard against appreciable rotarydisplacement of the said chaser-operating and chaser-supporting member with respect thereto but having capacity for movement longitudinally thereof.

8. In a movable-chaser tap, the combination with a body-member provided with a plurality of substantially-radial guide-ways; of a plurality of chasers; and a combined chaser-operating and chaser-supporting member mounted for reciprocating movement with respect to the said body-member and provided with means reciprocating with it for laterally supporting the said chasers; the said means for laterally supporting the said chasers being in turn supported in the guide-grooves in the said body-member against appreciable rotary displacement with respect thereto but with capacity for movement longitudinally thereof.

In testimony whereof, I have signed this specification.

ALBERT F. BREITENSTEIN. 

